The subject matter disclosed herein relates to the diaphragm of a turbine (e.g., gas and steam turbines) and, in particular, to repair of the aerodynamic partitions found in the flow path of the diaphragm.
Partitions in turbine diaphragms can incur damage during extended use. For example, in steam turbines, erosion and impact by foreign particulates on the partitions can damage critical components of the partitions including, for example, the trailing edge. Changes to the trailing edge modify the area through which steam and other exhaust gasses pass and can result in improper direction of steam flow relative to subsequent stages in the turbine. Overall, damage to the partitions can result in loss of turbine efficiency and unwanted vibrations.
During regularly scheduled outages of the turbine, teams can overhaul the steam turbine to refurbish the diaphragm. The overhaul includes inspection and repair of the partitions. The repair is meant to restore the partitions to re-establish proper steam flow and, thus, obtain better turbine efficiency. Achieving these goals often requires that the partitions are reshaped to effectively replicate the trailing edge before the onset of damage. However, because the partitions often have complex shapes, e.g., airfoils, significant effort is necessary to achieve the desired shape.
This effort includes, for example, taking steps to remove and/or to add material to the partition at the trailing edge. The steps may also include final contouring of the repaired partition, which works the new material back to the original aerodynamic shape of the partition. Typically, the repair techniques require operations (e.g., welding and machining) to occur in between the partitions, and, likely, in the flow path of steam (and other fluids). These locations are difficult to access. Moreover, because final contouring is important to performance of steam path, this step is conventionally done through manual operations that require precision tools and skilled technicians. Unfortunately, to properly address and repair the partitions using techniques that position welds in between the partitions involves a significant investment of money and time for highly skilled labor and, ultimately, can delay the turbine from coming back online in a timely manner.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.